Qhov sib txawv tseem ceeb ntawm qhov tseeb thiab pom tseeb qhov sib faib coefficient yog qhov tseeb muab faib coefficient yog txhais rau lub koomhaum koom ua ke whereas pom meej muab faib coefficient yog txhais rau qhov system ionized.
Ob nqe lus tseeb thiab pom tseeb muab faib coefficient yog siv feem ntau hauv kev tshuaj chemistry, hais txog kev tsim tshuaj. Nyob rau hauv cov ntaub ntawv ntawm cov tshuaj ionization, qhov tseeb muab faib coefficient muab faib cov tshuaj nyob rau hauv nws unionized lub xeev thaum pom meej muab faib coefficient muab faib cov tshuaj nyob rau hauv nws lub xeev ionized.
Tus nqi sib faib tiag tiag yog dab tsi?
Qhov tseeb muab faib coefficient yog qhov piv ntawm cov concentrations ntawm un-ionized hom ntawm ib tug compound nyob rau hauv ib tug sib tov ntawm ob theem immiscible. Feem ntau, peb tuaj yeem pom qhov tshwm sim no ua "P". Ob theem sib txawv yuav tsum nyob rau hauv sib npaug zos rau ib leeg los txiav txim qhov muab faib coefficient ntawm ob-theem system. Qhov piv no sawv cev rau qhov ntsuas ntawm kev solubility ntawm txhua hom un-ionized hauv qhov sib tov.
Daim duab 01: Kev sib npaug ntawm Organic Phase thiab Aqueous (Dej) Phase
Feem ntau, ob theem immiscible peb xav txog ntawm no yog cov kuab tshuaj. Feem ntau, nws yog dej-organic solvent system. Yog li ntawd, peb feem ntau xav txog hydrophilic-hydrophobic systems thaum txiav txim siab muab faib coefficient. Hauv qhov kev txiav txim siab no, qhov sib faib coefficient yog qhov ntsuas ntawm lipophilicity lossis hydrophobicity ntawm cov ntsiab lus uas peb xav tau. Qhov tshwm sim no tseem ceeb heev hauv kev txiav txim siab faib tshuaj thoob plaws hauv peb lub cev.
Pom meej Qhov Sib faib Coefficient yog dab tsi?
Pom meej muab faib coefficient yog qhov sib piv ntawm cov concentrations ntawm ionized thiab unionized hom ntawm ib tug compound nyob rau hauv ib tug sib tov ntawm ob theem immiscible. Peb tuaj yeem pom qhov no yog "Papp". Nws yog nyob ntawm qhov kev faib ua feem ntawm cov khoom tam sim no hauv cov tshuaj (cov khoom muaj nyob hauv cov tshuaj yog nyob ntawm pH ntawm cov tshuaj). Peb tuaj yeem siv qhov kho kom raug los qhia qhov pom tseeb qhov sib faib coefficient raws li qhov tseeb muab faib coefficient raws li hauv qab no;
Papp =P x funionized
Yog li ntawd, yog hais tias cov tshuaj yog ionized, ces tus nqi ntawm funionized ua 1 thiab Papp=P.. Yog tias 100 mg ntawm cov tshuaj ntxiv rau qhov sib xyaw tsis sib haum ntawm cov dej thiab cov kuab tshuaj organic uas pom tau tias yog 40 mg nyob rau theem organic thiab cov tshuaj ntxiv (66.7%) nyob rau hauv dej theem, qhov loj ntawm cov tshuaj nyob rau hauv dej theem yog (100-40)=60 mg. Qhov loj ntawm cov tshuaj ionized hauv dej yog (60 x 0.667)=40 mg. Qhov loj ntawm cov tshuaj unionized hauv dej yog (60 x 0.33)=20 mg. Yog li ntawd,
- Qhov concentration ntawm cov tshuaj nyob rau hauv cov organic theem (hauv 50.0 mL ntawm cov organic hnyav) yog (40/50)=0.8 mg / L.
- Qhov concentration ntawm cov tshuaj unionized hauv dej yog (20/50)=0.4 mg / L.
- Cov tshuaj tag nrho hauv dej yog (60/50)=1.2 mg/L.
- Cov feem pua ntawm cov tshuaj tau muab rho tawm mus rau theem organic yog (40 mg / 100 mg) x 100=40%.
- Qhov tseeb muab faib coefficient ntawm cov tshuaj unionized yog (tshuaj nyob rau hauv organic theem / unionized tshuaj nyob rau hauv dej)=0.8/0.4=2.
- Tus pom meej muab faib coefficient yog (tshuaj nyob rau hauv organic theem / tag nrho cov tshuaj nyob rau hauv dej theem)=(0.8/1.2)=0.67.
Dab tsi yog qhov txawv ntawm qhov tseeb thiab pom tseeb muab faib Coefficient?
Qhov tseeb thiab pom tseeb sib faib coefficients piav qhia txog kev faib tshuaj los ntawm lub cev. Qhov sib txawv tseem ceeb ntawm qhov tseeb thiab pom tseeb qhov sib faib coefficient yog qhov tseeb muab faib coefficient yog txhais rau ib lub unionized system whereas pom meej muab faib coefficient yog txhais rau ib tug ionized system.
Hauv qab infographic qhia txog qhov sib txawv ntawm qhov tseeb thiab pom tseeb muab faib coefficient.
Summary – True vs Apparent Partition Coefficient
Ob nqe lus tseeb thiab pom tseeb muab faib coefficient yog siv feem ntau hauv kev tshuaj chemistry, hais txog kev tsim tshuaj. Qhov tseeb thiab pom tseeb sib faib coefficients piav qhia txog kev faib cov tshuaj los ntawm qhov system. Qhov sib txawv tseem ceeb ntawm qhov tseeb thiab pom tseeb qhov sib faib coefficient yog qhov tseeb muab faib coefficient yog txhais rau ib qho kev sib koom ua ke thaum qhov pom tseeb muab faib coefficient yog txhais rau lub cev ionized.
